Introduction

Figure. Lateral view of part of the mantle and head of a 30 mm ML C. scabra showing tubercles. Photograph by R. Young.

C. scabra, the only species in the genus, is small (150 mm ML) and one of the most distinctive cranchiids.

The mantle is covered by large, multi-pointed cartilagenous tubercles (see Roper and Lu 1990, for a description of the tubercle structure). When disturbed, the squid often pulls its head and arms into the mantle cavity and folds its fins tightly against the mantle to form a turgid ball. The tubercules, presumably, provide some type of protection but it is unclear what predators are affected and how. In addition, the squid may ink into the mantle cavity, making the ball opaque. This was thought to be an aberrant behavior due to stress and confinement of shipboard aquaria until the same inking behavior was seen in cranchiids from submersibles (Hunt, 1996). The function of this behavior is unknown.

Brief diagnosis:

A cranchiin ...

with mantle covered with cartilagenous tubercules.

Characteristics

Tentacles

Suckers in a transverse row on club manus of equal size.

Diagonally set pairs of suckers and pad on distal 2/3 of tentacular stalk.

Comments

Behavior

The small C. scabra below, photographed in a shipboard aquarium, has retracted its head with arms and tentacles into the mantle cavity. The mantle has taken the shape of a sphere and the chromatophores have expanded. This response to disturbance perhaps makes their consumption by small-mouthed predators more difficult.

The photographs below, also taken in an aquarium, show two different color phases of the same squid. A typical transparent phase on the right and a peculiar anteriorly pigmented phase on the left. The half-pigmented phase was seen several times (D. Fenolio, pers. communication).

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Figure. Two side views of the same C. scabra, Sea of Japan, ca. 10 cm ML. Photographs by Danté Fenolio.

Life History

Small paralarvae lack tubercles and are similar in appearance to paralarvae of Liocranchia. However they can easily be separated from paralarvae of Liocranchia by the numerous, scattered chromatophores that cover much or all of the mantle and by the short, thick tentacles that appear to be rugose or, possibly, glandular. Note the sessile eyes. By 8 mm ML they have numerous tubercules.

About This Page

Page: Tree of Life
CranchiaLeach 1817. Cranchia scabraLeach 1817.
Authored by
Richard E. Young and Katharina M. Mangold (1922-2003).
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